1. Field of the Invention
The invention relates to a piezoelectric transducer, more particularly to a piezoelectric transducer module having interconnected transducer units.
2. Description of the Related Art
A transducer is a device that converts energy from one form to another. Transducers are commonly used for transformation of electrical energy into mechanical energy, and are extensively applied in the fields of electronics, electrical, mechanical and physics. Transducers for acoustic applications are commonly found in buzzers, earphones, microphones, speakers, etc.
Presently, piezoelectric material is commonly used as a basic component of transducers. When the piezoelectric material is subjected to a voltage drop, it mechanically deforms. Examples of materials that exhibit piezoelectric behavior include quartz, Rochelle salt, lead titanate zirconate cermics, barium titanate, and polyvinylidene fluoride.
FIG. 1 illustrates conventional electroacoustic transducer units 1 mounted on support members 2, respectively. Each of the transducer units 1 includes a metal substrate portion 11 coated with a piezoelectrically active coating 12 on opposite surfaces thereof. A set of contact wires is bonded to the piezoelectrically active coatings 12 and is adapted to be connected to an electrical signal source (not shown). Similarly, a contact wire is bonded to the substrate portion 11 and is adapted to be connected to the electrical signal source. In order to avoid undesired electrical contact between the contact wire of the substrate portion 11 and those of the piezoelectrically active coatings 12, a part of the piezoelectrically active coatings 12 on the substrate portion 11 is etched for bonding of the contact wire on the substrate portion 11. However, since each of the transducer units 1 is only 0.45 mm thick, a high level of accuracy is required during the contact wire bonding. This results in inefficient use of time, effort and material.
In U.S. Pat. No. 6,323,583, there is disclosed a piezoelectric bending transducer that includes a flat, electrically conductive supporting body having piezoelectrically active coatings on both sides. The piezoelectrically active coatings are omitted from one end of the supporting body, which is fixed in a connector base. Each of the coatings and the supporting body are electrically connected to a plug-in contact that includes an electrically conductive elastomer in a cavity in the connector base for accepting a contact pin that deforms the elastomer when the contact pin is inserted thereinto. The contact pins are adapted to be connected to an electrical signal source. This arrangement is particularly adapted for incorporation into a transducer module with transducers secured adjacent to each other in a common connector base.
Although the transducer in the aforesaid patent dispenses with the bonding of contact wires as required in the prior art of FIG. 1, etching of a part of the piezoelectrically active coatings is still needed, which results in manufacturing inefficiency and material waste. Further, since the transducer includes numerous small components, such as the connector base, plug-in contacts, etc., the difficulty in manufacturing the transducer is aggravated.